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Cheap flights from Portland, Maine to London from $336

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Portland, Maine to London departing on 9/2. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
0 bags

Discover deals from 900+ travel sites with momondo.

Find the cheapest flights from Portland, Maine to London

Cheap round-trip flights

Enter your travel dates to find the best prices.
Delta Logo
6:25 am - 7:15 am
PWM
-
LHR
19h 50m
1 stop
Delta Logo
9:55 am - 11:12 pm
LHR
-
PWM
18h 17m
2 stops
$729Delta
Fri, May 8 - Wed, May 13
KLM Logo
2:51 pm - 8:50 am
PWM
-
LHR
12h 59m
1 stop
KLM Logo
11:45 am - 12:43 am
LHR
-
PWM
17h 58m
2 stops
$730KLM
Mon, May 4 - Mon, May 18
Delta Logo
12:46 pm - 8:50 am
PWM
-
LHR
15h 04m
2 stops
Delta Logo
8:40 am - 11:09 pm
LHR
-
PWM
19h 29m
2 stops
$734Delta
Wed, May 6 - Mon, May 11
Delta Logo
1:35 pm - 7:15 am
PWM
-
LHR
12h 40m
1 stop
Delta Logo
1:25 pm - 10:23 pm
LHR
-
PWM
13h 58m
1 stop
$736Delta
Wed, Oct 14 - Tue, Oct 20
KLM Logo
12:46 pm - 7:10 am
PWM
-
LHR
13h 24m
1 stop
KLM Logo
12:50 pm - 12:43 am
LHR
-
PWM
16h 53m
1 stop
$737KLM
Wed, May 6 - Mon, May 11
Virgin Atlantic Logo
2:05 pm - 1:45 pm
PWM
-
LHR
18h 40m
2 stops
Virgin Atlantic Logo
6:30 am - 11:09 pm
LHR
-
PWM
21h 39m
2 stops
$750Virgin Atlantic
Fri, May 8 - Fri, May 15
Delta Logo
2:35 pm - 1:50 pm
PWM
-
LHR
18h 15m
2 stops
Delta Logo
8:40 am - 10:33 pm
LHR
-
PWM
18h 53m
2 stops
$761Delta
Thu, Sep 3 - Mon, Sep 7
Delta Logo
2:35 pm - 1:50 pm
PWM
-
LHR
18h 15m
2 stops
Delta Logo
12:50 pm - 11:59 pm
LHR
-
PWM
16h 09m
1 stop
$768Delta
Thu, Sep 3 - Mon, Sep 7
Virgin Atlantic Logo
6:57 pm - 1:15 pm
PWM
-
LHR
13h 18m
1 stop
Virgin Atlantic Logo
6:30 am - 10:33 pm
LHR
-
PWM
21h 03m
2 stops
$778Virgin Atlantic
Wed, Jul 29 - Fri, Aug 28
Virgin Atlantic Logo
6:00 am - 7:15 am
PWM
-
LHR
20h 15m
1 stop
Virgin Atlantic Logo
6:15 am - 10:33 pm
LHR
-
PWM
21h 18m
2 stops
$779Virgin Atlantic
Mon, Aug 10 - Wed, Aug 19

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Virgin Atlantic flights from Portland, Maine to London Heathrow Airport

Our best Virgin Atlantic deals on Portland, Maine to London Heathrow Airport flight tickets
Virgin Atlantic
May 8
PWM2:05 pmPortland
18h 40m
2 stops
LHR1:45 pmLondon Heathrow
May 15
LHR6:30 amLondon Heathrow
21h 39m
2 stops
PWM11:09 pmPortland
$750
Virgin Atlantic
Jul 29
PWM6:57 pmPortland
13h 18m
1 stop
LHR1:15 pmLondon Heathrow
Aug 28
LHR6:30 amLondon Heathrow
21h 03m
2 stops
PWM10:33 pmPortland
$778
Virgin Atlantic
Aug 10
PWM6:00 amPortland
20h 15m
1 stop
LHR7:15 amLondon Heathrow
Aug 19
LHR6:15 amLondon Heathrow
21h 18m
2 stops
PWM10:33 pmPortland
$779

United Airlines flights from Portland, Maine to London Heathrow Airport

Our best United Airlines deals on Portland, Maine to London Heathrow Airport flight tickets
United Airlines
Oct 11
PWM6:00 amPortland
10h 20m
1 stop
LHR9:20 pmLondon Heathrow
Oct 22
LHR9:30 amLondon Heathrow
18h 57m
2 stops
PWM11:27 pmPortland
$919
United Airlines
Sep 30
PWM6:00 amPortland
10h 25m
1 stop
LHR9:25 pmLondon Heathrow
Oct 10
LHR7:30 amLondon Heathrow
16h 54m
2 stops
PWM7:24 pmPortland
$921
United Airlines
Oct 11
PWM6:00 amPortland
10h 20m
1 stop
LHR9:20 pmLondon Heathrow
Oct 24
LHR7:45 amLondon Heathrow
11h 09m
1 stop
PWM1:54 pmPortland
$938

momondo Fare Finder

 
Customize your flight search to find flights from Portland, Maine to London Heathrow Airport that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, momondo users made 832,500 searches. Data last updated April 22, 2026.
Use the filters below to find and compare flights from Portland, Maine to London Heathrow Airport that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

PortlandLondon

PWM - LHR

PWMLHR

Portland

Fri 5/8

6:25 am-7:15 am

1 stop19h 50m

London Heathrow

Wed 5/13

9:55 am-11:12 pm

2 stops18h 17m

$729

PortlandLondon

PWM - LHR

PWMLHR

Portland

Mon 5/4

2:51 pm-8:50 am

1 stop12h 59m

London Heathrow

Mon 5/18

11:45 am-12:43 am

2 stops17h 58m

$730

PortlandLondon

PWM - LHR

PWMLHR

Portland

Wed 5/6

12:46 pm-8:50 am

2 stops15h 04m

London Heathrow

Mon 5/11

8:40 am-11:09 pm

2 stops19h 29m

$734
Quickest round-trip

PortlandLondon

PWM - LHR

PWMLHR

Portland

Wed 10/14

1:35 pm-7:15 am

1 stop12h 40m

London Heathrow

Tue 10/20

1:25 pm-10:23 pm

1 stop13h 58m

$736

PortlandLondon

PWM - LHR

PWMLHR

Portland

Wed 5/6

12:46 pm-7:10 am

1 stop13h 24m

London Heathrow

Mon 5/11

12:50 pm-12:43 am

1 stop16h 53m

$737

PortlandLondon

PWM - LHR

PWMLHR

Portland

Fri 5/8

2:05 pm-1:45 pm

2 stops18h 40m

London Heathrow

Fri 5/15

6:30 am-11:09 pm

2 stops21h 39m

$750

PortlandLondon

PWM - LHR

PWMLHR

Portland

Thu 9/3

2:35 pm-1:50 pm

2 stops18h 15m

London Heathrow

Mon 9/7

8:40 am-10:33 pm

2 stops18h 53m

$761

PortlandLondon

PWM - LHR

PWMLHR

Portland

Thu 9/3

2:35 pm-1:50 pm

2 stops18h 15m

London Heathrow

Mon 9/7

12:50 pm-11:59 pm

1 stop16h 09m

$768

PortlandLondon

PWM - LHR

PWMLHR

Portland

Wed 7/29

6:57 pm-1:15 pm

1 stop13h 18m

London Heathrow

Fri 8/28

6:30 am-10:33 pm

2 stops21h 03m

$778

PortlandLondon

PWM - LHR

PWMLHR

Portland

Mon 8/10

6:00 am-7:15 am

1 stop20h 15m

London Heathrow

Wed 8/19

6:15 am-10:33 pm

2 stops21h 18m

$779

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 19 resultsSorted by cheapest first
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See travel insights to London from

How to get the cheapest flight ticket from Portland, Maine to London Heathrow Airport

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest airline that flies from Portland to London Heathrow?

KLM, Delta, and United Airlines are the most popular carriers operating from Portland to London Heathrow

What airlines fly to London Heathrow Airport?

British Airways, Delta and American Airlines are the top three most popular airlines that fly to London Heathrow Airport from Portland, Maine according to our data. British Airways is the first choice among our users, with 50% of people opting to fly with this airline when traveling to London Heathrow Airport. Keep in mind that there are 16 different airlines that fly to London Heathrow Airport on a routine basis, so you have a few additional options to choose from.

When to book flights from Portland, Maine to London Heathrow Airport

Are you open to changing your travel dates? Check out the ideal times to fly from Portland, Maine to London Heathrow Airport according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap Portland, Maine to London Heathrow Airport (PWM to LHR) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Portland, Maine to London Heathrow Airport

Fastest flight time

10h 25m

Direct flights

None
The fastest flight from Portland, Maine to London Heathrow Airport takes 10h 25m
There are no direct flights from Portland, Maine to London Heathrow Airport. There are no popular flight routes from Portland, Maine to London Heathrow Airport.
Search flight deals

Frequently asked questions about flying from Portland, Maine to London Heathrow Airport

  • How far is Portland to London Heathrow by plane?

    The distance between Portland and London Heathrow is about 3170.3 mi. In terms of flight time, this usually takes a little over 10h 25m.

  • When did momondo last update prices for flights from Portland Airport to London Heathrow Airport?

    Prices for flights from Portland Airport to London Heathrow Airport refresh daily.

  • How many operators does momondo search for flights from Portland Airport to London Heathrow Airport?

  • How old do you have to be to fly from Portland Airport to London Heathrow Airport?

    Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Portland Airport to London Heathrow Airport.

  • What documentation or ID do you need to fly to London Heathrow Airport?

    The necessary travel and health documents for your London Heathrow Airport trip may vary depending on your travel plans and individual circumstances. Generally, you should have various documents, such as a national ID card or driver's license and a passport that is valid for six months beyond your scheduled arrival date. We recommend seeking advice from your airline or a trusted third party, such as IATA.

  • What is the most popular airline from Portland, Maine to London Heathrow Airport?

Best airlines flying from Portland, Maine to London Heathrow Airport

Compare and see reviews for airlines that fly from Portland, Maine to London Heathrow Airport with momondo
Airline
Rating
Free Cancellation
Price
United AirlinesPriceFrom $648Free CancellationRating
7.4
9,625 reviews
Search United Airlines flights

Traveling to a place near London?

Book flights to London if you plan to visit one of these locations
Hounslow
Gatwick
Milton Keynes
Dover
Luton
Hayes
Stratford-upon-Avon
Crawley
Slough
Wembley
Stansted
Watford
Croydon
Brentwood
Dartford
Cobham
Folkestone
Guildford
Romford
Harrow

Why use momondo?

Why should I use momondo to find a flight deal from Portland to London?

To find the flight that best suits your needs, momondo gathers a range of flights from a large pool of different airlines and agents; you can then use our insights and filters to find and book the right flight to London from Portland.

Can I find flights from Portland to London with flexible booking policies on momondo?

Yes. momondo enables you to select and highlight flights to London from Portland with this policy.

How can momondo help me find flights from Portland to London?

Once you have performed a search for Portland to London flights, momondo helps you find the right one by offering useful filters to narrow down your flight selection. Flights can be filtered by multiple factors such as airline, airport and price; but also by other criteria like aircraft type and payment method.

I’m not ready to book a flight from Portland to London right now. Can momondo alert me if prices change?

If you are simply researching potential flights to London, momondo offers a useful price alert feature which will track prices for flights to London from Portland and alert you when they change.

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